There is a risk in aircraft fuel systems of a build up of static electricity on one component in comparison to another component to which it is connected. In the prior art, a so-called bonding lead is connected to each side of the joint in order to electrically connect the components and prevent static build up. An example of such a bonding lead is described in the prior art section of US2008/0078880.
Bonding leads are traditionally made of highly conductive materials in different forms. These satisfy equipotential and electrostatic discharge requirements but allow the flow of lightning current across the joint. There is a risk that a break in such a bonding lead can result in intermittent contact with structure surrounding the bonding lead and a source of sparking should high levels of electricity flow in the lead, for instance during a lightning strike.